Have you got the OPC (safety lever on the handlebars) held back before checking the spark ? If you have & still got no spark take the top cover off to make sure the mechanism to it is clearing the cut out switch/ cable & not shorting out on anything. If it clears the contact, disconnect it anyway & then try for a spark, if there`s still no spark you may need a new ign. coil. If you fit a new coil, don`t forget to set the air-gap between the coil legs & the flywheel to 10 thou.
John
March 2011